A printhead die in an inkjet pen or print bar includes a plurality of fluid ejection elements on a surface of a silicon substrate. Fluid flows to the ejection elements through a fluid delivery slot formed in the substrate between opposing substrate surfaces. While fluid delivery slots adequately deliver fluid to fluid ejection elements, there are some disadvantages with such slots. From a cost perspective, for example, fluid delivery slots occupy valuable silicon real estate and add significant slot processing costs. In addition, lower printhead die costs are achieved in part through shrinking the die size. A smaller die size results in a tightening of the slot pitch and/or slot width in the silicon substrate. However, shrinking the die and the slot pitch increases the inkjet pen costs associated with integrating the small die into the pen during assembly. From a structural perspective, removing material from the substrate to form an ink delivery slot weakens the printhead die. Thus, when a single printhead die has multiple slots (e.g., to provide different colors in a multicolor printhead die, or to improve print quality and speed in a single color printhead die), the printhead die becomes increasingly fragile with the addition of each slot.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.